Whenever he has been confronted with a challenge — such as charges of involvement in the 2002 Gujarat riots, or, later, in the killings of Sohrabuddin Sheikh or Ishrat Jahan — he has invariably turned the tables on his political rivals and emerged stronger.

But the ghosts of Sohrabuddin and Jahan may yet return to haunt him.

That's because the Central Bureau of Investigation (CBI) has arrested his close aide and junior home minister (now resigned) Amit Shah. The charges are serious — murder (Sohrabuddin and his wife Kauserbi), extortion and criminal conspiracy.

"Shah was the only minister who enjoyed a free hand from Modi and he has turned out to an extortionist. This will damage his reputation and image," says political analyst Tridip Suhrid.

Modi's inability to protect Shah from arrest will also affect his carefully crafted image of invulnerability.

"He and his aides will no longer enjoy the unbridled power they have so far. Bureaucrats and, particularly, the police, will insist on proper written orders for anything controversial," says a retired bureaucrat.

But Modi and his team are already thinking ahead — and looking to turn L'affaire Shah into an advantage.

Six municipal corporations (Ahmedabad, Vadodara, Rajkot, Surat, Jamnagar and Bhavnagar), 22 district panchayats and more than a 100 block panchayats will go to the polls in October-November this year.

Currently, the BJP holds all the six municipal corporations and a majority of the other bodies.

"We will take this issue in the janata adalat (people's court). Our workers will highlight the Sohrabuddin issue and the misuse of the CBI by the UPA government at the Centre," says state BJP president R C Faldu.

"We will ask the public whether Sohrabuddin was a Sufi saint. Why is the Congress raising a hue and cry over the death of a gangster and extortionist?" another party leader who does not want to be identified adds.